Let the measure of BCD = aº. Because BCD and BAD form a circle, and a circle measures 360°, the measure of BAD IS 360 -
a. Because of the
theorem, mzA= 4 degrees and mC = 360
degrees. The sum of the measures of
angles A and Cis +350 -degrees, which is equal to 360° or 180°. Therefore, angles A and C are supplementary
because their measures add up to 180° Angles B and D are supplementary because the sum of the measures of the
angles in a quadrilateral is 360° m2A + m2C + m2B + m2D = 360°, and using substitution, 180° + m2B + m2D = 360°
so m2B + m2D = 180°
What is the missing information in the paragraph proof?

inscribed angle

polygon interior angle sum

quadrilateral angle sum

angle bisector